Humans ; Osteosarcoma ; metabolism ; Signal Transduction ; physiology ; TOR Serine-Threonine Kinases ; metabolism

Animals ; Eukaryotic Initiation Factors ; genetics ; metabolism ; Humans ; Phosphorylation ; physiology ; Proteomics ; Ribosomal Proteins ; genetics ; metabolism ; TOR Serine-Threonine Kinases ; genetics ; metabolism

BackgroundRecent studies have indicated that autophagy is involved in sepsis-induced myocardial dysfunction. This study aimed to investigate the change of autophagy in cecal ligation and puncture (CLP)-induced myocardium dysfunction and its relationship with mammalian target of rapamycin (mTOR) pathway.

MethodsTotally, 12 rats were randomly divided into CLP group or sham-operated (SHAM) group. Cardiac tissues were harvested 18 h after CLP or sham operation. Pathology was detected by hematoxylin and eosin staining, cardiac functions by echocardiography, distribution of microtubule-associated protein light chain 3 type II (LC3II) by immunohistochemical staining, and autophagic vacuoles by transmission electron microscopy. Moreover, phosphorylation of mTOR (p-mTOR), phosphorylation of S6 kinase-1 (PS6K1), and LC3II and p62 expression were measured by western blotting. Pearson's correlation coefficient was used to analyze the correlation of two parameters.

ResultsThe results by pathology and echocardiography revealed that there was obvious myocardial injury in CLP rats (left ventricle ejection fraction: SHAM 0.76 ± 0.06 vs. CLP 0.59 ± 0.11, P < 0.01; fractional shortening: SHAM 0.51 ± 0.09 vs. CLP 0.37 ± 0.06, P < 0.05). We also found that the autophagy process was elevated by CLP, the ratio of LC3II/LC3I was increased (P < 0.05) while the expression of p62 was decreased (P < 0.05) in the CLP rats, and there were also more autophagosomes and autolysosomes in the CLP rats. Furthermore, the mTOR pathway in CLP myocardium was inhibited when compared with the sham-operated rats; p-mTOR (P < 0.01) and PS6K1 (P < 0.05) were both significantly suppressed following CLP challenge. Interestingly, we found that the mTOR pathway was closely correlated with the autophagy processes. In our study, while p-mTOR in the myocardium was significantly correlated with p62 (r = 0.66, P = 0.02), PS6K1 was significantly positively correlated with p62 (r = 0.70, P = 0.01) and negatively correlated with LC3II (r = -0.71, P = 0.01).

ConclusionsThe autophagy process in the myocardium was accelerated in CLP rats, which was closely correlated with the inhibition of the mTOR pathway.

Animals ; Autophagy ; physiology ; Cecum ; injuries ; Echocardiography ; Immunohistochemistry ; Ligation ; Male ; Microscopy, Electron, Transmission ; Myocardium ; metabolism ; Rats ; Rats, Wistar ; Sepsis ; metabolism ; TOR Serine-Threonine Kinases ; metabolism

OBJECTIVE: To explore the changes of mTOR signal pathway in HeLa cells under different nutritional conditions infected with Coxsackie virus B3 (CVB3). METHODS: The HeLa cells were cultured with two methods: the conventional culture method cultured HeLa cells with medium with 10% fetal bovine serum for 24 h and changed the medium next day, and then infected with CVB3; the serum starvation method cultured HeLa cells with medium without fetal bovine serum for 24 h, and then infected with CVB3. The expression of the coat protein of CVB3, mTOR, p70S6K mRNA was detected with RT-PCR at different time points. RESULTS: The virus group showed the expressions of mTOR and p70S6K mRNA were significantly higher than those in the control group at 12 h and 24 h (P<0.05) in the conventional culture. The virus group showed the expressions of mTOR and p70S6K mRNA were lower than those in the control group (all P<0.05) in the starvation serum. The expression of mTOR mRNA in the starvation serum virus group was higher than that in the conventional culture virus group (all P<0.05) and the control group. The expression of p70S6K mRNA was not significantly different in the two groups (P>0.05). CONCLUSION CVB3 can down-regulate the expressions of mTOR and p70S6K mRNA. The mTOR expression in the starvation serum is higher than that in the conventional culture.
Cell Culture Techniques ; Down-Regulation ; Enterovirus B, Human ; pathogenicity ; HeLa Cells ; Humans ; RNA, Messenger ; genetics ; metabolism ; Signal Transduction ; physiology ; TOR Serine-Threonine Kinases ; genetics ; metabolism

Antibiotics, Antineoplastic ; therapeutic use ; Apoptosis ; Cell Cycle ; Humans ; Neoplasms ; drug therapy ; metabolism ; pathology ; Neovascularization, Pathologic ; etiology ; Phosphatidylinositol 3-Kinases ; metabolism ; Protein Kinases ; physiology ; Proto-Oncogene Proteins c-akt ; metabolism ; Signal Transduction ; Sirolimus ; therapeutic use ; TOR Serine-Threonine Kinases

Studies of epilepsy have mainly focused on the membrane proteins that control neuronal excitability. Recently, attention has been shifting to intracellular proteins and their interactions, signaling cascades and feedback regulation as they relate to epilepsy. The mTOR (mammalian target of rapamycin) signal transduction pathway, especially, has been suggested to play an important role in this regard. These pathways are involved in major physiological processes as well as in numerous pathological conditions. Here, involvement of the mTOR pathway in epilepsy will be reviewed by presenting; an overview of the pathway, a brief description of key signaling molecules, a summary of independent reports and possible implications of abnormalities of those molecules in epilepsy, a discussion of the lack of experimental data, and questions raised for the understanding its epileptogenic mechanism.
Astrocytes/metabolism ; Cell Death ; Epilepsy/diet therapy/drug therapy/*metabolism/virology ; Humans ; Ketogenic Diet ; Protein Binding/physiology ; Protein Kinase Inhibitors/therapeutic use ; Receptors, Cannabinoid/metabolism ; Signal Transduction/*physiology ; Synapses/metabolism ; TOR Serine-Threonine Kinases/antagonists & inhibitors/*metabolism ; Temporal Lobe/metabolism

OBJECTIVEIn order to provide theoretic evidence of exercise preventing insulin resistance, we studied the effects of high-fat diet and aerobic exercise on expression of mammalian target of rapamycin/ribosomal protein kinase (mTOR/S6K1) in skeletal muscle of insulin resistant mice.

METHODS8-week old, C57BL/6 mice were divided into two groups: which are normal chow and high-fat diet groups, each group has 20 animals feeding by normal chow and high fat diet respectively. 8-weeks later, mice from high fat diet group were proved to have insulin resistance symptoms and after that time point the mice were regrouped. The normal chow group was randomly divided into normal chow diet control group (NC) and normal chow exercise group (NE), and the high fat diet group was randomly divided into high fat diet control group (HC) and high fat diet exercise group (HE). All exercise groups were required to running on treadmill for 6 weeks. Mice were acclimatized to the motorized treadmill by running 60 min per day at the intensity of 75% VO2max five days per week for 6 weeks. By the end of training, we observed the changes of glucose tolerance by oral glucose tolerance test and morphology of pancreatic islet under microscope. Insulin concentration was measured by ELISA. Northern blot and Western blot were performed to detect mTOR, S6K1 (and/or pS6K1-Thr389) mRNA and protein expression in skeletal muscle.

RESULTSBy comparing with NC group, the effect of high-fat diet increased the body weight, fasting serum insulin level and the area of pancreatic islet of the mice in HC group significantly. Furthermore, glucose tolerance was impaired. After 6-week aerobic exercise, above value of descriptive index were significantly decreased in skeletal muscle in HE group. In addition, OGTT was also improved. The expression of mTOR, S6K1 (and/or pS6K1-Thr389) mRNA and protein were significantly decreased.

CONCLUSIONmTOR/S6K1 signaling pathway plays an important role in the development of diet induced insulin resistance. Aerobic exercise attenuates insulin resistance by increasing skeletal muscle insulin sensitivity evidenced by increased energy metabolism decreased activity of mTOR/S6K1 signaling pathway.

Animals ; Body Weight ; Diet, High-Fat ; Glucose Tolerance Test ; Insulin ; blood ; Insulin Resistance ; Male ; Mice ; Mice, Inbred C57BL ; Muscle, Skeletal ; metabolism ; Physical Conditioning, Animal ; physiology ; Ribosomal Protein S6 Kinases, 90-kDa ; metabolism ; Signal Transduction ; TOR Serine-Threonine Kinases ; metabolism

This paper aimed to investigate the role and potential mechanism of p53 on primordial follicle activation. Firstly, the p53 mRNA expression in the ovary of neonatal mice at 3, 5, 7 and 9 days post-partum (dpp) and the subcellular localization of p53 were detected to confirm the expression pattern of p53. Secondly, 2 dpp and 3 dpp ovaries were cultured with p53 inhibitor Pifithrin-μ (PFT-μ, 5 μmol/L) or equal volume of dimethyl sulfoxide for 3 days. The function of p53 in primordial follicle activation was determined by hematoxylin staining and whole ovary follicle counting. The proliferation of cell was detected by immunohistochemistry. The relative mRNA levels and protein levels of the key molecules involved in the classical pathways associated with the growing follicles were examined by immunofluorescence staining, Western blot and real-time PCR, respectively. Finally, rapamycin (RAP) was used to intervene the mTOR signaling pathway, and ovaries were divided into four groups: Control, RAP (1 μmol/L), PFT-μ (5 μmol/L), PFT-μ (5 μmol/L) + RAP (1 μmol/L) groups. The number of follicles in each group was determined by hematoxylin staining and whole ovary follicle counting. The results showed that the expression of p53 mRNA was decreased with the activation of primordial follicles in physiological condition. p53 was expressed in granulosa cells and oocyte cytoplasm of the primordial follicles and growing follicles, and the expression of p53 in the primordial follicles was higher than that in the growing follicles. Inhibition of p53 promoted follicle activation and reduced the primordial follicle reserve. Inhibition of p53 promoted the proliferation of the granulosa cells and oocytes. The mRNA and protein expression levels of key molecules in the PI3K/AKT signaling pathway including AKT, PTEN, and FOXO3a were not significantly changed after PFT-μ treatment, while the expression of RPS6/p-RPS6, the downstream effectors of the mTOR signaling pathway, was upregulated. Inhibition of both p53 and mTOR blocked p53 inhibition-induced primordial follicle activation. Collectively, these findings suggest that p53 may inhibit primordial follicle activation through the mTOR signaling pathway to maintain the primordial follicle reserve.
Female ; Animals ; Mice ; Tumor Suppressor Protein p53/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Phosphatidylinositol 3-Kinases/metabolism* ; Hematoxylin ; Signal Transduction/physiology* ; TOR Serine-Threonine Kinases ; Sirolimus ; RNA, Messenger

Animals ; Antineoplastic Agents ; therapeutic use ; Apoptosis ; Apoptosis Regulatory Proteins ; metabolism ; Autophagy ; physiology ; Beclin-1 ; Humans ; Membrane Proteins ; metabolism ; Neoplasms ; drug therapy ; metabolism ; pathology ; Signal Transduction ; TOR Serine-Threonine Kinases ; metabolism ; Tumor Suppressor Protein p53 ; metabolism

BACKGROUNDGrowing evidence from population and clinic based studies showed that obstructive sleep apnea (OSA) and its characterizing chronic intermittent hypoxia (IH) were independently associated with the development of type 2 diabetes mellitus. However, the pathogenesis by which OSA induces glucose metabolic disorders is not clear. We determined changes in pancreatic β cell mass and the mammalian target of rapamycin (mTOR)/hypoxia inducible factor 1 (HIF-1)/vascular endothelial growth factor A (VEGF-A) pathway following IH exposure.

METHODSA controlled gas delivery system regulated the flow of nitrogen and oxygen into a customized cage housing mice during the experiment. Twenty-four male wild C57BL/6J mice were either exposed to IH (n = 12) or intermittent air as a control (n = 12) for 56 days. Mice were anaesthetized and sacrificed after exposure, pancreas samples were dissected for immunofluorescent staining. Insulin and DAPI staining labelled islet β cells. Insulin positive area and β cell number per islet were measured. P-S6, HIF-1α and VEGF-A staining were performed to detect the activation of mTOR/HIF-1/VEGF-A pathway.

RESULTSAfter eight weeks of IH exposure, insulin positive area increased by an average of 18.5% (P < 0.05). The β cell number per islet increased (92 vs. 55, respectively for IH and the control groups, P < 0.05) with no change in the size of individual β cells. Islet expression of HIF-1α and VEGF-A were higher in IH group than control group, and percentage of p-S6 positive β cell also increased after IH exposure (16.8% vs. 4.6% respectively for IH and the control groups, P < 0.05).

CONCLUSIONThe number of pancreatic β cells increased as did the activity of the mTOR/HIF-1/VEGF-A pathway after exposure to IH.

Animals ; Hypoxia ; pathology ; Hypoxia-Inducible Factor 1 ; physiology ; Insulin-Secreting Cells ; metabolism ; pathology ; Male ; Mice ; Mice, Inbred C57BL ; Signal Transduction ; TOR Serine-Threonine Kinases ; physiology ; Vascular Endothelial Growth Factor A ; physiology